Cummins Engine Diagnostic Scanners

Written by the YOUCANIC technicians in Towson, Maryland, from the UCAN-HD-A coverage database and our own shop work. Updated October 24, 2026.

Cummins is an engine story. The same ISX or ISB can sit in a Freightliner, a Kenworth, a Peterbilt, an International, a Western Star, a motorhome, a school bus or a loader, and the coverage database behind the UCAN-HD-A lists Cummins the way the engine does: by engine family and controller, not by truck. Pick the engine on the tablet and you get the engine control module with its codes, live data, the cylinder cutout, the regeneration and the DEF doser tests. The tools below are what we use to get a Cummins powered truck out of the yard without a dealer laptop. Pick by what you need to do, then check the connector note.

Which Scanner Do I Need For A Cummins?

CLASS 4 TO 8 TRUCKS, BUSES, ENGINES AND EQUIPMENT

UCAN-HD-A

Full system heavy duty scanner on SAE J1939, J1708 and J1587 with a wireless VCI and the 9 pin, 6 pin and OBD2 connectors in the case. Reads the Cummins engine control module by family, runs Cylinder Cutout Test, DPF regeneration and the DEF doser tests, and graphs live data. Free updates, no subscription. The tool to own if you keep a Cummins working.

PICKUPS, VANS AND CARS

UCAN-II Pro, new or open box

Full system, bidirectional, lifetime free updates, with a built in TPMS module. The scanner for the light duty pickups and vans, including the Cummins powered RAM, through the RAM and Dodge pages. It does not speak J1939 or J1708, so it is not the tool for a Class 8 truck; for a mixed fleet you want both.

What The UCAN-HD-A Does On A Cummins

• ✓ Read ECU Information, Read FaultCode, Erase FaultCode and Live Data on the Engine control module of every Cummins family in the database, from CELECT to ISX and the QS industrial engines
• ✓ Cylinder Cutout Test to find the weak or dead cylinder, one injector at a time
• ✓ Aftertreatment Diesel Particulate Filter Regeneration on the engines that list it, with soot and temperature on the live data screen
• ✓ DEF tests: Diesel Exhaust Fluid Doser Pump Override Test, Doser Pump Manual Override Test, Dual Doser Override Test, Doser Air Supply Valve Click Test, Doser Pump Air Solenoid Click Test, Doser System Heater Test and the Doser Purge Counter
• ✓ EGR: EGR Valve Test, EGR Valve Actuator Test and EGR Delta Pressure Auto Zero Test
• ✓ Features and Parameters, Trip Information, Maintenance Monitor and Engine State Monitor for reading how the engine is set up and used
• ✓ Gas Throttle Control Test on the gas engines, Starter Lockout Relay Driver Override Test, SAE J1939 Datalink Control Test and Setup for Dynamometer
• ✓ Live data graphed, PID merge, recording and playback, and PDF reports from the tablet

Service Functions By Job On A Cummins

On the tablet you pick the Cummins entry, then the engine family, then the Engine control module, the function category and the routine. These are the routines the coverage database lists for Cummins, grouped by the job you are doing. Names are as they appear on the tablet. Coverage varies by engine family and ECM software, so check yours before you order.

What The Scanner Sees On A Cummins

Cummins entries in the coverage database are engine families and controllers, each with one module, the Engine control module, and the function categories on top of it. Three groups from the list:

Symptom, Then The Routine That Fixes It

• Rough idle, smoke or a cylinder that sounds dead: Cylinder Cutout Test, one injector at a time.
• DPF lamp or high soot load: Aftertreatment Diesel Particulate Filter Regeneration with the live data screen open.
• DEF dosing or heater codes: Diesel Exhaust Fluid Doser Pump Override Test, Doser System Heater Test and the air supply valve and air solenoid click tests.
• EGR flow or delta pressure codes after a sensor or cooler job: EGR Valve Test, EGR Valve Actuator Test and EGR Delta Pressure Auto Zero Test.

Frequently Asked Questions

Will it run a DPF regeneration on my ISX15 or ISB6.7?

Aftertreatment Diesel Particulate Filter Regeneration is a listed special function on the Cummins entry for the aftertreatment era engines. Confirm your exact family and controller in the coverage checker before you buy for that job.

Can it cut out cylinders on a Cummins?

Yes. Cylinder Cutout Test is in the Actuation test category on the Cummins engine control module, so you can find the weak injector before you pull any.

Does it matter which truck the Cummins is in?

No. Pick the Cummins entry and the engine family; the engine routines are the same in a Freightliner, a Kenworth, an International or a bus. For chassis modules, use the truck maker's entry.

Can it change the road speed limit on my Cummins?

Features and Parameters reads the engine settings, and the UCAN-HD-A sets the road speed governor on supported engines. Parameters protected by a password stay with Cummins software, so ask support with your engine family first.

Which connector does my truck have?

Most Cummins powered trucks use the 9 pin Deutsch round connector; older J1708 trucks use the 6 pin. The UCAN-HD-A kit includes both plus the OBD2 connector.

How do I know my exact engine and function are covered?

Use the coverage checker by engine family, or call 1-888-959-4265, Monday to Friday 9 AM to 4 PM Eastern, with the VIN and the engine, and a technician will tell you plainly. If it does not do what you need, we will say so. Every scanner also comes with 31 day returns, no questions asked.

See the truck pages for Freightliner, Kenworth and Peterbilt and International, the scanners by make hub, the service functions explained one job at a time, and the step by step repair guides on youcanic.com.